1. Technical Field
A method for forming an isolation film in a semiconductor device is shown and described.
2. Description of the Related Art
Recently, with the higher-integration and higher-density of semiconductor devices, technologies which can improve the gap-fill characteristics of isolation films has become increasingly important.
Generally, a typical method for forming an isolation film in a semiconductor device includes forming a first insulating film in pre-existing trenches, performing an etch-back process and then forming a second insulating film to fill the trenches.
However, if the etch-back process is performed using a process gas such as C2F6 gas that contains F ions, a in the etch-back process, a FSG (Fluorinated Silicon Glass) film is formed on a first high-density plasma (HDP) oxide film. The F ions in the FSG film are diffused into the interface between the isolation film and elements while undergoing subsequent treatment processes, etc. Therefore, there is a problem in that the F ions of the FSG film degrade the characteristics of the resulting device.